The nearshore Antarctic environment is subject to increasing anthropogenic impact, yet the ecological processes influencing some of its most dominant species remain poorly understood. We examined patterns of the distribution and abundance of the Antarctic amphipod Orchomenella franklini in relation to the local environment. Samples of benthic sediment were collected in East Antarctica across several spatial and temporal scales and were analysed for the abundance of O. franklini and various sediment properties. O. franklini was found to reach extremely high densities (<41000 m^-2), yet abundance was strongly heterogeneous on all spatial scales tested. Temporal variation in abundance was also significant and was location-specific, potentially reflecting fluctuations in food supply and variable conditions resulting from ice disturbance. Principal component analysis and generalised additive modelling revealed evidence of a relationship between the distribution of O. franklini and the sediment, which was consistent with its deposit-feeding trophic niche. Generally, the abundance of O. franklini increased with decreasing sediment grain size and increasing trace element concentration. Abundance also peaked at high (though not maximum) total organic carbon content. This is one of the first empirical demonstrations of a correlation between discrete physical sediment traits and the abundance of an infaunal benthic species in the Antarctic, with evidence consolidated from 2 geographic regions. The influence of local conditions on the abundance of O. franklini provides insight on the heterogeneity of Antarctic benthic ecosystems.

Item Type:	Refereed Article
Keywords:	benthic sediment, peracarid crustacean, population density, metals, grain size, anthropogenic impact, environmental change
Research Division:	Biological Sciences
Research Group:	Zoology
Research Field:	Invertebrate Biology
Objective Division:	Environment
Objective Group:	Flora, Fauna and Biodiversity
Objective Field:	Antarctic and Sub-Antarctic Flora, Fauna and Biodiversity
UTAS Author:	Baird, HP (Dr Helen Baird)
ID Code:	98695
Year Published:	2014
Web of Science® Times Cited:	2
Deposited By:	IMAS Research and Education Centre
Deposited On:	2015-02-25
Last Modified:	2015-04-21
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